Thermochromic Fibers Via Electrospinning

Cholesteryl ester liquid crystals exhibit thermochromic properties related to the existence of a twisted nematic phase. We formulate ternary mixtures of cholesteryl benzoate (CB), cholesteryl pelargonate (CP), and cholesteryl oleyl carbonate (COC) to achieve thermochromic behavior. We aim to achieve thermochromic fibers by incorporating the liquid crystal formulations into electrospun fibers. Two method of incorporating the liquid crystal (LC) are compared (1) coaxial electrospinning and (2) blend electrospinning. Importantly, coaxially electrospinning with LC and solvent in the core preserves the thermochromic properties of the LC so that thermochromic fibers are achieved. For blend electrospinning, addition of LC can suppress bead formation which we attribute to strong intermolecular interactions. Polymer and solvent selection for blend electrospinning are important to ensure solvent induced phase separation so that thermochromic fibers are achieved.